The present invention relates to a semiconductor structure and a method of fabricating the same. More particularly, the present invention relates to a complementary metal oxide semiconductor (CMOS) device, e.g., a field effect transistor (FET).
Besides exhibiting intriguing quantum behaviors even at room temperature, carbon-based nanotubes exhibit at least two important characteristics, a nanotube may be either metallic or semiconducting depending on its chirality, i.e., conformational geometry. Metallic nanotubes may carry an extremely large current density with constant resistivity. Semiconducting nanotubes may be electrically switched “on” or “off” as field effect transistors (FETs). The two types may be covalently joined (sharing electrons). These characteristics point to nanotubes as excellent materials for making nanometer-sized semiconductor circuits. Similar properties exist for other one-dimensional nanostructures.
Carbon-based nanotubes and other like one-dimensional nanostructures are thus becoming strategically important for post-Si FET scaling. However, there is no known self-aligned process comparable to conventional CMOS technology. A self-aligned process for a CMOS device including one-dimensional nanostructures would provide a simpler sequence of processing steps as compared to a non-self-aligned process and it reduces processing error that typically occurs when a non-self-aligned process is used. Moreover, a self-aligned process provides a structure having reduced parasitics as compared to a non-self-aligned structure.